The present invention relates generally to the field of purge systems utilized in the servicing of mechanical refrigeration systems. More particularly, in one form the present invention is directed to a method and apparatus for removing a lubricant from a contaminated refrigerant material discharged from an evaporator of a mechanical refrigeration system.
Mechanical refrigeration systems generally function in a continuous fashion and reuse the refrigerant material circulating in the refrigeration system. Typically, three pieces of equipment including an evaporator, a condenser and a compressor are utilized in the refrigeration system. In the evaporator, cold liquid refrigerant is warmed by absorbing heat from the medium to be cooled. As the liquid refrigerant temperature rises, the liquid refrigerant is evaporated and forms a warm refrigerant vapor. The warm refrigerant vapor is then delivered to the compressor. The compressor compresses the refrigerant vapor to raise the pressure of the vapor and thereby lower the temperature at which the refrigerant vapor will condense. This resulting hot refrigerant vapor is then piped to the condenser to be cooled and change phase to the liquid state. The liquid refrigerant is then transported to the evaporator where the refrigeration cycle begins over again.
Mechanical refrigeration system designers will appreciate that there are many different styles, types and designs for compressors. It is well recognized that all compressors in one way or another mechanically compress the refrigerant vapor to cause a pressure rise in the gas. The mechanical action needed to increase the pressure requires moving parts and the moving parts require the use of lubricants to reduce friction between the associated mechanical components. The inevitable wear on the compressor components and the practical limitations on mechanical seals allows for the intermixing of the lubricant and refrigerant material within the mechanical refrigeration system. Over time, the refrigerant material becomes contaminated with lubricant material and other various substances such as acids. Contamination of the refrigerant material with lubricant reduces the refrigerant materials ability to perform the refrigeration cycle efficiently. Additionally, the loss of lubricant from the compressor requires that lubricant must be periodically added to the compressor to account for the loss of lubricant.
A purge system for removing substantially all of the lubricant from the contaminated liquid refrigerant material of the refrigerant system has significant advantages. The removal of the lubricant from the refrigerant material results in marked increase in the heat transfer from the medium to be cooled and an enhanced efficiency of the system. The reclaimed refrigerant material with the lubricant removed therefrom can be pumped back into the mechanical refrigeration system for continued reuse in the refrigeration cycle. The lubricant that has been separated from the contaminated refrigerant material can be reclaimed and/or returned to the compressor for lubricating the mechanical components therein.
There remains a need for a purge unit and method of operation for removing a lubricant from the contaminated refrigerant material utilized in a mechanical refrigeration system. The present invention satisfies this need in a novel and non-obvious way.